Russia began evacuating thousands more people from its border regions on Thursday after Ukraine said it was advancing deeper into the country in a lightning incursion aimed at forcing Moscow to slow its advance along the rest of the front.
The biggest foreign attack on sovereign Russian territory since World War Two unfurled on August 6 when thousands of Ukrainian troops smashed through Russia's Western border in an embarrassment for the Russian top military brass.
Supported by swarms of drones, heavy artillery and tanks, Ukrainian units have since carved out a sliver of the world's biggest nuclear power and battles were ongoing along a front about 18 km inside Russian territory on Thursday.
Kursk's acting governor, Alexei Smirnov, said that the Glushkov district, which has a population of 20,000, was being evacuated. At least 200,000 people have so far been evacuated from the border regions, according to Russian data.
Ukrainian President Volodymyr Zelenskiy said on Wednesday that his forces had advanced a few kilometres and that the goal of replenishing an 'exchange fund' of prisoners of war was being achieved. One Ukrainian official said Kyiv was carving out a buffer zone to protect its population against attack.
Russia's defence ministry said on Thursday that its forces had shot down Ukrainian drones over the neighbouring Belgorod region of Russia and that Sukhoi-34 bombers had pummeled Ukrainian positions in Kursk.
Russia's defence ministry also reported intense battles along the Ukraine front, and said that its troops had taken better positions at several points.
While the Ukrainian attack has embarrassed Moscow, revealed the weakness of its border defences and changed the public narrative of the war, Russian officials said what they cast as a Ukrainian "invasion" would not change the course of the war.
Russia, which invaded Ukraine in 2022, has been advancing for most of the year along the 1000 km front in Ukraine for much of the year and has a vast numerical superiority. It controls 18 per cent of Ukraine.